|This USGS-funded competitive 2-year research program provides a US federal GS-12 base salary plus operational funds (e.g., fieldwork, instrumentation, meetings, publications). The application deadline for this program is 17 February 2015.
The Impact Sea-Level Rise, Storms, and Tsunamis on Low-lying US Atolls
Observations (e.g., Church and White, 2006) show that global sea level is rising at a rate almost double the Intergovernmental Panel on Climate Change’s (IPCC) 2001 report and recent estimates (e.g., Pfeffer et al., 2008) that include rise due to thermal expansion and ice melting show a most likely sea level increase by the end of the century of up to 2.0 m. Sea-level rise is particularly critical for unconsolidated low-lying coral atoll islets, many of which have maximum elevations of less than 4 m above present sea level (Woodroffe, 2008; Dickinson, 2009). Subaerial atoll islets are Holocene features that support 2000 year-old cultures, yet the amount of land and water available for human habitation, water and food sources, and ecosystems is limited and extremely vulnerable to inundation from sea-level rise and waves (Fletcher and Richmond, 2010). Large changes in sea level relative to the elevation of atoll islets threaten terrestrial ecosystems (Hatfield et al., 2012) and infrastructure (Hoeke et al., 2013) by storm wave-induced overwash and inundation by tsunamis. In addition, storm and tsunami events can contaminate the thin freshwater lens underlying islets with saltwater (Terry and Falkland, 2010), making the islands unsuitable for agriculture and/or habitation.
Changes in sea level may also affect the sustainability of tidewater ecosystems, and rising sea levels may exacerbate the impacts of storm and tsunami waves on adjacent coral reefs that buffer the atoll islets from waves (Storlazzi et al., 2011). For example, storm wave- and tsunami-driven overwash events on US-managed Pacific atolls in 2008, 2009, and 2011 ruined freshwater drinking supplies, killed crops, destroyed infrastructure, and killed hundreds of thousands of federally-protected species. At the same time, our understanding of how short (wind waves) and longer waves (infragravity and tsunami waves) propagate over complex bathymetry and topography that has high hydrodynamic roughness due to the presence of bedrock outcrops and/or corals is limited, and thus our ability to accurately model overwash and inundation in these settings is poor.
We invite postdoctoral scientists to propose research projects to determine the impact of accelerated sea-level rise on the critical hydrodynamic and geologic processes that affect atoll islets. The Mendenhall Fellow will develop and test innovative means for measuring and predicting rates of change to atolls using state-of-the-art process-response models, including impacts of storms and tsunamis, and assimilations of disparate data types such as lidar- and satellite-derived high-resolution topography and bathymetry, coastal geomorphology, and historic and real-time oceanographic and meteorologic measurements. We envision that this research could be accomplished using a number of different approaches. One approach could be analysis of existing remote sensing, geologic, and tectonic data on all US atolls to feed a Bayesian model. Another approach would be fieldwork on an atoll with a logistical base (i.e., Midway, Wake, Johnston, and Palmyra NWRs) to acquire topographic, bathymetric, and geologic information for a process-based numerical model to be tested on different atoll islet configurations (islet cross-sectional area, islet proximity to atoll rim, windward or leeward islet location on atoll, etc.). Specific tools that could be employed include digital grain-size imaging systems, geophysical subsurface mapping tools, and high-resolution acoustic and laser mapping systems to understand current geologic processes and coupled hydrodynamic-sediment transport-geomorphic numerical models for the longer-term goal of predicting how future climate change, sea level rise, and extreme wave events may impact atoll systems. These predictions will form the basis for determining which DOI- or DOD-managed atolls are most at risk and provide the foundation for quantifying the impact of sea level rise on specific atolls under US jurisdiction.
The postdoctoral fellow will have ample opportunities for interdisciplinary collaborations in geology, oceanography, physics, hydrology, statistics, spatial data analyses, numerical modeling, remote sensing, and engineering. She/he will be able to develop partnerships with researchers from different USGS science areas, other federal agencies (USDA, USFWS, NOAA, USACE), and academia. The postdoctoral researcher will be at the forefront of interdisciplinary research and will participate in significantly improving our understanding of the impact of climate change and sea-level rise on the sustainability of atoll systems.
Proposed Duty Station: Santa Cruz, CA
Areas of Ph.D.: Geology, oceanography, computer science, civil engineering, coastal engineering or related fields (candidates holding a Ph.D. in other disciplines but with knowledge and skills relevant to the Research Opportunity may be considered).
Qualifications: Applicants must meet one of the following qualifications: Research Geologist, Research Oceanographer, Research Hydrologist, Research Geographer, or Civil Engineer (This type of research is performed by those who have backgrounds for the occupations stated above. However, other titles may be applicable depending on the applicant's background, education, and research proposal. The final classification of the position will be made by the USGS Human Resources specialist.)